Magnetic Detector Probe with Segmented Coils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic sensor probes for detecting magnetic nanoparticles in tissue localization during surgery face challenges such as thermal effects, diamagnetic interference, and eddy currents, which reduce sensitivity and accuracy, and are often bulky.
Innovation Solution
A magnetic susceptometer probe design with a core material of high thermal diffusivity and low thermal expansion, featuring staggered sense and drive coils, a secondary magnetic drive field, and a method to measure side lobe amplitudes at specific frequencies to distinguish nanoparticle signals from noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the probe size is reduced to improve maneuverability and patient comfort, then the sensitivity and detection capability deteriorate due to smaller coil size and increased thermal effects
Solution Approach 1:
The probe is divided into multiple independent coil assemblies, each with its own drive and sense coils. This segmentation allows each coil to be optimized for sensitivity while the distributed arrangement reduces thermal interference between coils, as each coil operates semi-independently with its own thermal zone.
Solution Approach 2:
The coil assemblies are nested within a layered structure where drive coils and sense coils are interleaved. This nesting allows the coils to be packed efficiently in a compact volume while maintaining sufficient separation to reduce thermal coupling, achieving both small size and high sensitivity.
2Measurement precision
If the coil density is increased to improve detection sensitivity, then thermal effects increase causing coil shift and signal degradation
Solution Approach 1:
The probe structure incorporates localized thermal management features at each coil assembly, including thermal isolation elements and heat dissipation paths specific to each coil's location. This allows each coil to be densely packed for sensitivity while its local thermal environment is controlled to prevent thermal drift.
Solution Approach 2:
The coil assemblies are pre-positioned and mechanically constrained within the probe housing before operation. This preliminary mechanical stabilization prevents thermal expansion from causing coil shift during operation, maintaining geometric stability despite temperature changes.
3Device complexity
If the probe structure is simplified to reduce manufacturing complexity, then the ability to reduce diamagnetic interference and eddy currents deteriorates
Solution Approach 1:
The probe employs composite construction with non-magnetic, non-conductive materials for the core structure and coil formers. This composite approach simultaneously reduces diamagnetic interference from the body and minimizes eddy currents in the probe itself, while the modular assembly keeps manufacturing complexity manageable.
Solution Approach 2:
Non-magnetic, non-conductive intermediary materials are placed between the coils and the body tissue, and between coil layers. These intermediary elements act as barriers that reduce diamagnetic interference and prevent eddy current formation, while being simple to manufacture and integrate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances sensitivity and accuracy by minimizing thermal effects, reducing interference, and maintaining performance in a smaller probe size, effectively detecting magnetic nanoparticles while distinguishing them from other metallic objects and body diamagnetic responses.
Implementation Method 1
two drive coils, one each of the drive coils being located in a respective one of the regions
Implementation Method 2
two sense coils, one each of the sense coils being located in a respective one of the regions
Implementation Method 3
The probe core may comprise a material with a thermal diffusivity of substantially ≥20 x 10^-6
Implementation Method 4
a source of a secondary magnetic drive field. The source of a secondary magnetic drive field may be a coil located on the probe
Data Source
Figure 1~2
Figure 3
Figure 4~6B
AI summary
A probe and method for detecting magnetic particles. In one embodiment, the probe includes a probe core having a first end and a second end, the probe core defining two regions for containing coils of wire, one of the regions being adjacent the first end of the cylindrical probe core; two sense coils, one each of the sense coils being located in a respective one of the regions; and two drive coils, one each of the drive coils being located in a respective one of the regions, wherein the regions are separated by a distance equal to or greater than the diameter of one of the coils and a source of a secondary magnetic drive field. In another embodiment, the frequency of the drive signal of the secondary magnetic drive field is less than the frequency of the drive signal of the primary drive coils.